Conventional monolithic microwave integrated circuit (MMIC) power amplifiers, depending on the frequency band, are power matched using lumped element capacitors, inductors and transmission lines on a Gallium Arsenide (GaAs), Silicon (Si), or Silicon Carbide (SiC) substrate. Very broad band (i.e., multi-octave) high-power amplifiers are difficult to power match due to extremely low impedances, and cumulative non-idealities in the lumped element and distributed matching elements at opposite ends of the frequency bands.
The cumulative loss of the matching elements can make broadband matching networks very lossy. In multi-octave bandwidth designs, required frequency operation of the amplifier can approach the resonant frequency of the inductors and capacitors used for impedance matching, which contributes significant non-idealities into the design and synthesis process. The significant non-idealities are due to the limited bandwidth and Q (quality factor) of the lumped element inductors and capacitors themselves. The use of a single stage MMIC compatible impedance transformer to overcome the limited bandwidth, Q, and non-idealities of lumped element matching elements has been demonstrated in power amplifiers with limited success.
It would be desirable to have a method for output matching of high power amplifiers over broad bandwidth that overcomes the limited bandwidth, Q, and non-idealities of lumped element matching elements.